XXXVI INTRODUCTION. 



to dolomite,, and from dolomite to serpentine. 39 Yet Dr. Dawson 

 has actually laid himself open to his friend's sally ! 



It is one of the most singular things connected with the 

 eozoonal controversy that we have repeatedly asserted (and the 

 assertion has been supported by evidences which have not been 

 disproved) that the " proper wall " is nothing more than a modifi- 

 cation of chrysotile ; and it is equally singular that none of the 

 " original workers" ineozoonism has made any signs of his having 

 observed any such evidences, particularly considering that they 

 present themselves to us in almost every specimen that has come 

 under our observation. At last, however, and after the lapse of 

 more than a decade, a specimen of the kind has occurred to Dr. 

 Dawson the one which he imagines exhibits the calcite of the 

 tl proper wall " replaced by serpentine. 



Not having seen the specimen^ it would, of course, be unsafe 

 for us to offer any decided opinion upon it ; but we are strongly 

 tempted to suggest that it is nothing more than a corresponding 

 one to cases which we have repeatedly brought under notice. 

 Our first memoir contains a figure, which has been copied in our 

 present Plate VI. fig. 2. It represents typical chrysotile in 

 two places, particularly at a, in its incipient condition, passing 

 insensibly into that of serpentine. Are not Dr. Dawon's 

 " walls of the skeleton," " still retaining traces of the canals," 

 an instance in point? If so, we should not hesitate to say 

 that it consists of chrysotile in its incipient stage of de- 

 velopment (a, fig. 1, PI. IX.), and that, instead of being a 

 case of " the change of calcite into serpentine," it is simply 

 the latter mineral in the intermediate stage, between its amor- 

 phous condition and that of true chrysotile. 



Dr. Dawson cannot see any relation between chrysotile and 

 the " proper wall." Having observed " chrysotile veins " irre- 

 gularly intersecting the lamellae of " EOZOQU" he remarks : 

 < ( I have no hesitation in stating that the assertion that these 

 chrysotile veins are identical with or similar to the proper wall 

 of Eozoon, either in structure or distribution, is wholly without 



